Imoto Mayumi, Yoshida Koji, Maeda Yasuhiro, Nakae Ken-Ichi, Kudo Masatoshi, Sakurabayashi Ikunosuke, Yamada Toshiyuki, Kamisako Toshinori
Clin Lab. 2017 May 1;63(5):983-989. doi: 10.7754/Clin.Lab.2017.170106.
We encountered a rare case of Waldenstrom macroglobulinemia with temporary appearance of 7S IgM half molecule and with monoclonal proteins binding to agarose gel.
The patient's serum and urine were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The N-terminal amino acid sequences of the IgM with abnormal mass (68 kDa) were determined and compared with those of known immunoglobulin.
The 68 kDa IgM consisted of a defective μ chain (36 kDa) and an intact κ chain. N-terminal amino acid sequence analysis demonstrated that the defective μ chain had the variable region of IgM. The agarose gel-binding ability of the IgM-κ M-protein was lost after reduction or alkaline treatment of serum.
The 7S half molecule IgM in the present case may miss a large part of the constant region of the µ chain.
我们遇到一例罕见的华氏巨球蛋白血症病例，出现了7S IgM半分子的短暂现象，且单克隆蛋白与琼脂糖凝胶结合。
使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和免疫印迹法分析患者的血清和尿液。测定了质量异常（68 kDa）的IgM的N端氨基酸序列，并与已知免疫球蛋白的序列进行比较。
68 kDa的IgM由一条缺陷性μ链（36 kDa）和一条完整的κ链组成。N端氨基酸序列分析表明，缺陷性μ链具有IgM的可变区。血清经还原或碱性处理后，IgM-κ M蛋白的琼脂糖凝胶结合能力丧失。
本例中的7S半分子IgM可能缺失了μ链恒定区的大部分。
